First-Principles Study of Electron Linewidths in Graphene

TL;DR

This study uses first-principles calculations to analyze the quasiparticle linewidths in n-doped graphene, revealing the distinct wavevector dependencies of electron-electron and electron-phonon interactions and their combined effect on experimental linewidths.

Contribution

It provides a detailed first-principles analysis of quasiparticle linewidths in graphene, highlighting the different behaviors of electron-electron and electron-phonon interactions.

Findings

Electron-electron linewidths vary significantly with wavevector.

Electron-phonon linewidths are nearly wavevector-independent.

Combined interactions explain experimental linewidths.

Abstract

We present first-principles calculations of the linewidths of low-energy quasiparticles in n-doped graphene arising from both the electron-electron and the electron-phonon interactions. The contribution to the electron linewidth arising from the electron-electron interactions vary significantly with wavevector at fixed energy; in contrast, the electron-phonon contribution is virtually wavevector-independent. These two contributions are comparable in magnitude at a binding energy of ~0.2 eV, corresponding to the optical phonon energy. The calculated linewidths, with both electron-electron and electron-phonon interactions included, explain to a large extent the linewidths seen in recent photoemission experiments.